MARKETABLE SECURITIES - Schedule of Gross Unrealized Losses And Fair Value of Available For Sale Securities (Details) $ in Thousands	Mar. 31, 2020 USD ($)
Marketable Securities [Line Items]
Total fair value of available-for-sale securities in a continuous unrealized loss position for less than twelve months	$ 353,173
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position for less than twelve months	(2,474)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer, accumulated loss	0
Total fair value of available-for-sale securities in a continuous unrealized loss position	353,173
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position	(2,474)
Cash equivalents
Marketable Securities [Line Items]
Total fair value of available-for-sale securities in a continuous unrealized loss position for less than twelve months	55,608
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position for less than twelve months	(58)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer, accumulated loss	0
Total fair value of available-for-sale securities in a continuous unrealized loss position	55,608
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position	(58)
Cash equivalents | Cash equivalents
Marketable Securities [Line Items]
Total fair value of available-for-sale securities in a continuous unrealized loss position for less than twelve months
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position for less than twelve months
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer, accumulated loss
Total fair value of available-for-sale securities in a continuous unrealized loss position
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position
Cash equivalents | Commercial paper
Marketable Securities [Line Items]
Total fair value of available-for-sale securities in a continuous unrealized loss position for less than twelve months	9,971
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position for less than twelve months	(8)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer, accumulated loss	0
Total fair value of available-for-sale securities in a continuous unrealized loss position	9,971
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position	(8)
Cash equivalents | Corporate bonds
Marketable Securities [Line Items]
Total fair value of available-for-sale securities in a continuous unrealized loss position for less than twelve months	36,944
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position for less than twelve months	(48)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer, accumulated loss	0
Total fair value of available-for-sale securities in a continuous unrealized loss position	36,944
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position	(48)
Cash equivalents | Asset backed securities
Marketable Securities [Line Items]
Total fair value of available-for-sale securities in a continuous unrealized loss position for less than twelve months	8,693
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position for less than twelve months	(2)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer, accumulated loss	0
Total fair value of available-for-sale securities in a continuous unrealized loss position	8,693
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position	(2)
Marketable securities
Marketable Securities [Line Items]
Total fair value of available-for-sale securities in a continuous unrealized loss position for less than twelve months	297,565
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position for less than twelve months	(2,416)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer, accumulated loss	0
Total fair value of available-for-sale securities in a continuous unrealized loss position	297,565
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position	(2,416)
Marketable securities | Commercial paper
Marketable Securities [Line Items]
Total fair value of available-for-sale securities in a continuous unrealized loss position for less than twelve months	7,952
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position for less than twelve months	(12)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer, accumulated loss	0
Total fair value of available-for-sale securities in a continuous unrealized loss position	7,952
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position	(12)
Marketable securities | Corporate bonds
Marketable Securities [Line Items]
Total fair value of available-for-sale securities in a continuous unrealized loss position for less than twelve months	245,886
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position for less than twelve months	(2,168)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer, accumulated loss	0
Total fair value of available-for-sale securities in a continuous unrealized loss position	245,886
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position	(2,168)
Marketable securities | Asset backed securities
Marketable Securities [Line Items]
Total fair value of available-for-sale securities in a continuous unrealized loss position for less than twelve months	12,208
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position for less than twelve months	(102)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer, accumulated loss	0
Total fair value of available-for-sale securities in a continuous unrealized loss position	12,208
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position	(102)
Marketable securities | Certificates of deposit
Marketable Securities [Line Items]
Total fair value of available-for-sale securities in a continuous unrealized loss position for less than twelve months	31,519
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position for less than twelve months	(134)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer	0
Debt securities, available-for-sale, continuous unrealized loss position, 12 months of longer, accumulated loss	0
Total fair value of available-for-sale securities in a continuous unrealized loss position	31,519
Total gross unrealized losses of available-for-sale securities in a continuous unrealized loss position	$ (134)